示例－检查网络状态
以下示例显示 netstat -i 命令的输出，其中显示了用于 TCP/IP 流量的接口的状态。
$ netstat -i Name Mtu Net/Dest Address Ipkts Ierrs Opkts Oerrs Collis Queue lo0 8232 software localhost 1280 0 1280 0 0 0 eri0 1500 loopback venus 1628480 0 347070 16 39354 0 |
此输出显示了机器在每个接口中传输和接收的包数。对于具有活动网络通信流量的机器而言，Ipkts 和 Opkts 都应持续增加。
将冲突计数 (Collis) 除以传出的包数 (Opkts)，以计算网络冲突率。在上一示例中，冲突率为 11%。如果网络范围内的冲突率大于 5% 至 10 %，则表示可能存在问题。
将输入错误数除以输入包的总数 (Ierrs/Ipkts)，以计算输入包的错误率。输出包的错误率等于输出错误数除以输出包的总数 (Oerrs/Opkts)。如果输入错误率较高（高于 0.25%）则主机可能在删除包。
以下示例显示 netstat -s 命令的输出，其中显示了 UDP、TCP、ICMP 和 IGMP 协议的按协议的统计信息。
UDP
udpInDatagrams =196543 udpInErrors = 0
udpOutDatagrams =187820
TCP
tcpRtoAlgorithm = 4 tcpRtoMin = 200
tcpRtoMax = 60000 tcpMaxConn = -1
tcpActiveOpens = 26952 tcpPassiveOpens = 420
tcpAttemptFails = 1133 tcpEstabResets = 9
tcpCurrEstab = 31 tcpOutSegs =3957636
tcpOutDataSegs =2731494 tcpOutDataBytes =1865269594
tcpRetransSegs = 36186 tcpRetransBytes =3762520
tcpOutAck =1225849 tcpOutAckDelayed =165044
tcpOutUrg = 7 tcpOutWinUpdate = 315
tcpOutWinProbe = 0 tcpOutControl = 56588
tcpOutRsts = 803 tcpOutFastRetrans = 741
tcpInSegs =4587678
tcpInAckSegs =2087448 tcpInAckBytes =1865292802
tcpInDupAck =109461 tcpInAckUnsent = 0
tcpInInorderSegs =3877639 tcpInInorderBytes =-598404107
tcpInUnorderSegs = 14756 tcpInUnorderBytes =17985602
tcpInDupSegs = 34 tcpInDupBytes = 32759
tcpInPartDupSegs = 212 tcpInPartDupBytes =134800
tcpInPastWinSegs = 0 tcpInPastWinBytes = 0
tcpInWinProbe = 456 tcpInWinUpdate = 0
tcpInClosed = 99 tcpRttNoUpdate = 6862
tcpRttUpdate =435097 tcpTimRetrans = 15065
tcpTimRetransDrop = 67 tcpTimKeepalive = 763
tcpTimKeepaliveProbe= 1 tcpTimKeepaliveDrop = 0
IP
ipForwarding = 2 ipDefaultTTL = 255
ipInReceives =11757234 ipInHdrErrors = 0
ipInAddrErrors = 0 ipInCksumErrs = 0
ipForwDatagrams = 0 ipForwProhibits = 0
ipInUnknownProtos = 0 ipInDiscards = 0
ipInDelivers =4784901 ipOutRequests =4195180
ipOutDiscards = 0 ipOutNoRoutes = 0
ipReasmTimeout = 60 ipReasmReqds = 8723
ipReasmOKs = 7565 ipReasmFails = 1158
ipReasmDuplicates = 7 ipReasmPartDups = 0
ipFragOKs = 19938 ipFragFails = 0
ipFragCreates =116953 ipRoutingDiscards = 0
tcpInErrs = 0 udpNoPorts =6426577
udpInCksumErrs = 0 udpInOverflows = 473
rawipInOverflows = 0
ICMP
icmpInMsgs =490338 icmpInErrors = 0
icmpInCksumErrs = 0 icmpInUnknowns = 0
icmpInDestUnreachs = 618 icmpInTimeExcds = 314
icmpInParmProbs = 0 icmpInSrcQuenchs = 0
icmpInRedirects = 313 icmpInBadRedirects = 5
icmpInEchos = 477 icmpInEchoReps = 20
icmpInTimestamps = 0 icmpInTimestampReps = 0
icmpInAddrMasks = 0 icmpInAddrMaskReps = 0
icmpInFragNeeded = 0 icmpOutMsgs = 827
icmpOutDrops = 103 icmpOutErrors = 0
icmpOutDestUnreachs = 94 icmpOutTimeExcds = 256
icmpOutParmProbs = 0 icmpOutSrcQuenchs = 0
icmpOutRedirects = 0 icmpOutEchos = 0
icmpOutEchoReps = 477 icmpOutTimestamps = 0
icmpOutTimestampReps= 0 icmpOutAddrMasks = 0
icmpOutAddrMaskReps = 0 icmpOutFragNeeded = 0
icmpInOverflows = 0
IGMP:
0 messages received
0 messages received with too few bytes
0 messages received with bad checksum
0 membership queries received
0 membership queries received with invalid field(s)
0 membership reports received
0 membership reports received with invalid field(s)
0 membership reports received for groups to which we belong
0 membership reports sent
|
以下示例显示 netstat -r 命令的输出，其中显示了 IP 路由表。
Routing Table: Destination Gateway Flags Ref Use Interface ------------------ -------------------- ----- ----- ------ --------- localhost localhost UH 0 2817 lo0 earth-bb pluto U 3 14293 eri0 224.0.0.0 pluto U 3 0 eri0 default mars-gate UG 0 14142 |
表 30–2 中介绍了 netstat -r 报告中的字段。
表 30–2 netstat -r 命令的输出|
字段名 |
|
说明 |
|---|---|---|
|
Flags |
U G H D |
路由向上。 路由通过网关。 路由到主机。 路由是使用重定向动态创建的。 |
|
Ref |
|
显示共享相同链路层的当前路由数。 |
|
Use |
|
表示发出的包的数目。 |
|
Interface |
|
列出用于路由的网络接口。 |
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